Paul Bettany was 25 in Sharpe's Waterloo when he played the character 'Prince William of Orange'.
That was over 27 years ago in 1997.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 52, and has starred in 56 movies in total, 52 of those since Sharpe's Waterloo was released.
In Sharpe's Waterloo, I think Paul Bettany looks: